1. 23 Sep, 2014 6 commits
    • Brian Foster's avatar
      xfs: only writeback and truncate pages for the freed range · 8b5279e3
      Brian Foster authored
      xfs_free_file_space() only affects the range of the file for which space
      is being freed. It currently writes and truncates the page cache from
      the start offset of the free to EOF.
      
      Modify xfs_free_file_space() to write back and truncate page cache of
      just the range being freed.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      8b5279e3
    • Brian Foster's avatar
      xfs: writeback and inval. file range to be shifted by collapse · f71721d0
      Brian Foster authored
      The collapse range operation currently writes the entire file before
      starting the collapse to avoid changes in the in-core extent list due to
      writeback causing the extent count to change. Now that collapse range is
      fsb based rather than extent index based it can sustain changes in the
      extent list during the shift sequence without disruption.
      
      Modify xfs_collapse_file_space() to writeback and invalidate pages
      associated with the range of the file to be shifted.
      xfs_free_file_space() currently has similar behavior, but the space free
      need only affect the region of the file that is freed and this could
      change in the future.
      
      Also update the comments to reflect the current implementation. We
      retain the eofblocks trim permanently as a best option for dealing with
      delalloc extents. We don't shift delalloc extents because this scenario
      only occurs with post-eof preallocation (since data must be flushed such
      that the cache can be invalidated and data can be shifted). That means
      said space must also be initialized before being shifted into the
      accessible region of the file only to be immediately truncated off as
      the last part of the collapse. In other words, the eofblocks trim will
      happen anyways, we just run it first to ensure the file remains in a
      consistent state throughout the collapse.
      
      Finally, detect and fail explicitly in the event of a delalloc extent
      during the extent shift. The implementation does not support delalloc
      extents and the caller is expected to prevent this scenario in advance
      as is done by collapse.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      f71721d0
    • Brian Foster's avatar
      xfs: refactor single extent shift into xfs_bmse_shift_one() helper · a979bdfe
      Brian Foster authored
      xfs_bmap_shift_extents() has a variety of conditions and error checks
      that make the logic difficult to follow and indent heavy. Refactor the
      loop body of this function into a new xfs_bmse_shift_one() helper. This
      simplifies the error checks, eliminates index decrement on merge hack by
      pushing the index increment down into the helper, and makes the code
      more readable by reducing multiple levels of indentation.
      
      This is a code refactor only. The behavior of extent shift and collapse
      range is not modified.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      a979bdfe
    • Brian Foster's avatar
      xfs: refactor shift-by-merge into xfs_bmse_merge() helper · ddb19e31
      Brian Foster authored
      The extent shift mechanism in xfs_bmap_shift_extents() is complicated
      and handles several different, non-deterministic scenarios. These
      include extent shifts, extent merges and potential btree updates in
      either of the former scenarios.
      
      Refactor the code to be more linear and readable. The loop logic in
      xfs_bmap_shift_extents() and some initial error checking is adjusted
      slightly. The associated btree lookup and update/delete operations are
      condensed into single blocks of code. This reduces the number of
      btree-specific blocks and facilitates the separation of the merge
      operation into a new xfs_bmse_merge() and xfs_bmse_can_merge() helpers.
      
      This is a code refactor only. The behavior of extent shift and collapse
      range is not modified.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      ddb19e31
    • Brian Foster's avatar
      xfs: track collapse via file offset rather than extent index · 2c845f5a
      Brian Foster authored
      The collapse range implementation uses a transaction per extent shift.
      The progress of the overall operation is tracked via the current extent
      index of the in-core extent list. This is racy because the ilock must be
      dropped and reacquired for each transaction according to locking and log
      reservation rules. Therefore, writeback to prior regions of the file is
      possible and can change the extent count. This changes the extent to
      which the current index refers and causes the collapse to fail mid
      operation. To avoid this problem, the entire file is currently written
      back before the collapse operation starts.
      
      To eliminate the need to flush the entire file, use the file offset
      (fsb) to track the progress of the overall extent shift operation rather
      than the extent index. Modify xfs_bmap_shift_extents() to
      unconditionally convert the start_fsb parameter to an extent index and
      return the file offset of the extent where the shift left off, if
      further extents exist. The bulk of ths function can remain based on
      extent index as ilock is held by the caller. xfs_collapse_file_space()
      now uses the fsb output as the starting point for the subsequent shift.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      2c845f5a
    • Dave Chinner's avatar
      xfs: ensure WB_SYNC_ALL writeback handles partial pages correctly · 0d085a52
      Dave Chinner authored
      XFS has been having trouble with stray delayed allocation extents
      beyond EOF for a long time. Recent changes to the collapse range
      code has triggered erroneous EBUSY errors on page invalidtion for
      block size smaller than page size filesystems. These
      have been caused by dirty buffers beyond EOF on a partial page which
      do not get written to disk during a sync.
      
      The issue is that write-ahead in xfs_cluster_write() finds such a
      partial page and handles it by leaving the page dirty but pushing it
      into a writeback state. This used to work just fine, as the
      write_cache_pages() code would then find the dirty partial page in
      the next mapping tree lookup as the dirty tag is still set.
      
      Unfortunately, when we moved to a mark and sweep approach to
      writeback to fix other writeback sync issues, we broken this. THe
      act of marking the page as under writeback now clears the TOWRITE
      tag in the radix tree, even though the page is still dirty. This
      causes the TOWRITE tag to be cleared, and hence the next lookup on
      the mapping tree does not find the dirty partial page and so doesn't
      try to write it again.
      
      This same writeback bug was found recently in ext4 and fixed in
      commit 1c8349a1 ("ext4: fix data integrity sync in ordered mode")
      without communication to the wider filesystem community. We can use
      exactly the same fix here so the TOWRITE flag is not cleared on
      partial page writes.
      
      cc: stable@vger.kernel.org # dependent on 1c8349a1Root-cause-found-by: default avatarBrian Foster <bfoster@redhat.com>
      Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      
      0d085a52
  2. 02 Sep, 2014 7 commits
    • Brian Foster's avatar
      xfs: trim eofblocks before collapse range · 41b9d726
      Brian Foster authored
      xfs_collapse_file_space() currently writes back the entire file
      undergoing collapse range to settle things down for the extent shift
      algorithm. While this prevents changes to the extent list during the
      collapse operation, the writeback itself is not enough to prevent
      unnecessary collapse failures.
      
      The current shift algorithm uses the extent index to iterate the in-core
      extent list. If a post-eof delalloc extent persists after the writeback
      (e.g., a prior zero range op where the end of the range aligns with eof
      can separate the post-eof blocks such that they are not written back and
      converted), xfs_bmap_shift_extents() becomes confused over the encoded
      br_startblock value and fails the collapse.
      
      As with the full writeback, this is a temporary fix until the algorithm
      is improved to cope with a volatile extent list and avoid attempts to
      shift post-eof extents.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      
      41b9d726
    • Dave Chinner's avatar
      xfs: xfs_file_collapse_range is delalloc challenged · 1669a8ca
      Dave Chinner authored
      If we have delalloc extents on a file before we run a collapse range
      opertaion, we sync the range that we are going to collapse to
      convert delalloc extents in that region to real extents to simplify
      the shift operation.
      
      However, the shift operation then assumes that the extent list is
      not going to change as it iterates over the extent list moving
      things about. Unfortunately, this isn't true because we can't hold
      the ILOCK over all the operations. We can prevent new IO from
      modifying the extent list by holding the IOLOCK, but that doesn't
      prevent writeback from running....
      
      And when writeback runs, it can convert delalloc extents is the
      range of the file prior to the region being collapsed, and this
      changes the indexes of all the extents in the file. That causes the
      collapse range operation to Go Bad.
      
      The right fix is to rewrite the extent shift operation not to be
      dependent on the extent list not changing across the entire
      operation, but this is a fairly significant piece of work to do.
      Hence, as a short-term workaround for the problem, sync the entire
      file before starting a collapse operation to remove all delalloc
      ranges from the file and so avoid the problem of concurrent
      writeback changing the extent list.
      Diagnosed-and-Reported-by: default avatarBrian Foster <bfoster@redhat.com>
      Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      
      
      1669a8ca
    • Brian Foster's avatar
      xfs: don't log inode unless extent shift makes extent modifications · ca446d88
      Brian Foster authored
      The file collapse mechanism uses xfs_bmap_shift_extents() to collapse
      all subsequent extents down into the specified, previously punched out,
      region. This function performs some validation, such as whether a
      sufficient hole exists in the target region of the collapse, then shifts
      the remaining exents downward.
      
      The exit path of the function currently logs the inode unconditionally.
      While we must log the inode (and abort) if an error occurs and the
      transaction is dirty, the initial validation paths can generate errors
      before the transaction has been dirtied. This creates an unnecessary
      filesystem shutdown scenario, as the caller will cancel a transaction
      that has been marked dirty.
      
      Modify xfs_bmap_shift_extents() to OR the logflags bits as modifications
      are made to the inode bmap. Only log the inode in the exit path if
      logflags has been set. This ensures we only have to cancel a dirty
      transaction if modifications have been made and prevents an unnecessary
      filesystem shutdown otherwise.
      Signed-off-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      
      ca446d88
    • Dave Chinner's avatar
      xfs: use ranged writeback and invalidation for direct IO · 7d4ea3ce
      Dave Chinner authored
      Now we are not doing silly things with dirtying buffers beyond EOF
      and using invalidation correctly, we can finally reduce the ranges of
      writeback and invalidation used by direct IO to match that of the IO
      being issued.
      
      Bring the writeback and invalidation ranges back to match the
      generic direct IO code - this will greatly reduce the perturbation
      of cached data when direct IO and buffered IO are mixed, but still
      provide the same buffered vs direct IO coherency behaviour we
      currently have.
      Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      
      7d4ea3ce
    • Dave Chinner's avatar
      xfs: don't zero partial page cache pages during O_DIRECT writes · 834ffca6
      Dave Chinner authored
      Similar to direct IO reads, direct IO writes are using 
      truncate_pagecache_range to invalidate the page cache. This is
      incorrect due to the sub-block zeroing in the page cache that
      truncate_pagecache_range() triggers.
      
      This patch fixes things by using invalidate_inode_pages2_range
      instead.  It preserves the page cache invalidation, but won't zero
      any pages.
      
      cc: stable@vger.kernel.org
      Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      
      834ffca6
    • Chris Mason's avatar
      xfs: don't zero partial page cache pages during O_DIRECT writes · 85e584da
      Chris Mason authored
      xfs is using truncate_pagecache_range to invalidate the page cache
      during DIO reads.  This is different from the other filesystems who
      only invalidate pages during DIO writes.
      
      truncate_pagecache_range is meant to be used when we are freeing the
      underlying data structs from disk, so it will zero any partial
      ranges in the page.  This means a DIO read can zero out part of the
      page cache page, and it is possible the page will stay in cache.
      
      buffered reads will find an up to date page with zeros instead of
      the data actually on disk.
      
      This patch fixes things by using invalidate_inode_pages2_range
      instead.  It preserves the page cache invalidation, but won't zero
      any pages.
      
      [dchinner: catch error and warn if it fails. Comment.]
      
      cc: stable@vger.kernel.org
      Signed-off-by: default avatarChris Mason <clm@fb.com>
      Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      85e584da
    • Dave Chinner's avatar
      xfs: don't dirty buffers beyond EOF · 22e757a4
      Dave Chinner authored
      generic/263 is failing fsx at this point with a page spanning
      EOF that cannot be invalidated. The operations are:
      
      1190 mapwrite   0x52c00 thru    0x5e569 (0xb96a bytes)
      1191 mapread    0x5c000 thru    0x5d636 (0x1637 bytes)
      1192 write      0x5b600 thru    0x771ff (0x1bc00 bytes)
      
      where 1190 extents EOF from 0x54000 to 0x5e569. When the direct IO
      write attempts to invalidate the cached page over this range, it
      fails with -EBUSY and so any attempt to do page invalidation fails.
      
      The real question is this: Why can't that page be invalidated after
      it has been written to disk and cleaned?
      
      Well, there's data on the first two buffers in the page (1k block
      size, 4k page), but the third buffer on the page (i.e. beyond EOF)
      is failing drop_buffers because it's bh->b_state == 0x3, which is
      BH_Uptodate | BH_Dirty.  IOWs, there's dirty buffers beyond EOF. Say
      what?
      
      OK, set_buffer_dirty() is called on all buffers from
      __set_page_buffers_dirty(), regardless of whether the buffer is
      beyond EOF or not, which means that when we get to ->writepage,
      we have buffers marked dirty beyond EOF that we need to clean.
      So, we need to implement our own .set_page_dirty method that
      doesn't dirty buffers beyond EOF.
      
      This is messy because the buffer code is not meant to be shared
      and it has interesting locking issues on the buffer dirty bits.
      So just copy and paste it and then modify it to suit what we need.
      
      Note: the solutions the other filesystems and generic block code use
      of marking the buffers clean in ->writepage does not work for XFS.
      It still leaves dirty buffers beyond EOF and invalidations still
      fail. Hence rather than play whack-a-mole, this patch simply
      prevents those buffers from being dirtied in the first place.
      
      cc: <stable@kernel.org>
      Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
      Reviewed-by: default avatarBrian Foster <bfoster@redhat.com>
      Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
      
      22e757a4
  3. 25 Aug, 2014 5 commits
    • Linus Torvalds's avatar
      Linux 3.17-rc2 · 52addcf9
      Linus Torvalds authored
      52addcf9
    • Linus Torvalds's avatar
      Merge tag 'nfs-for-3.17-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs · f01bfc97
      Linus Torvalds authored
      Pull NFS client fixes from Trond Myklebust:
       "Highlights:
      
         - more fixes for read/write codepath regressions
           * sleeping while holding the inode lock
           * stricter enforcement of page contiguity when coalescing requests
           * fix up error handling in the page coalescing code
      
         - don't busy wait on SIGKILL in the file locking code"
      
      * tag 'nfs-for-3.17-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
        nfs: Don't busy-wait on SIGKILL in __nfs_iocounter_wait
        nfs: can_coalesce_requests must enforce contiguity
        nfs: disallow duplicate pages in pgio page vectors
        nfs: don't sleep with inode lock in lock_and_join_requests
        nfs: fix error handling in lock_and_join_requests
        nfs: use blocking page_group_lock in add_request
        nfs: fix nonblocking calls to nfs_page_group_lock
        nfs: change nfs_page_group_lock argument
      f01bfc97
    • Linus Torvalds's avatar
      Merge tag 'renesas-sh-drivers-for-v3.17' of... · dd5957b7
      Linus Torvalds authored
      Merge tag 'renesas-sh-drivers-for-v3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas
      
      Pull SH driver fix from Simon Horman:
       "Confine SH_INTC to platforms that need it"
      
      * tag 'renesas-sh-drivers-for-v3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas:
        sh: intc: Confine SH_INTC to platforms that need it
      dd5957b7
    • Linus Torvalds's avatar
      Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus · 497c01dd
      Linus Torvalds authored
      Pull MIPS fixes from Ralf Baechle:
       "Pretty much all across the field so with this we should be in
        reasonable shape for the upcoming -rc2"
      
      * 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus:
        MIPS: OCTEON: make get_system_type() thread-safe
        MIPS: CPS: Initialize EVA before bringing up VPEs from secondary cores
        MIPS: Malta: EVA: Rename 'eva_entry' to 'platform_eva_init'
        MIPS: EVA: Add new EVA header
        MIPS: scall64-o32: Fix indirect syscall detection
        MIPS: syscall: Fix AUDIT value for O32 processes on MIPS64
        MIPS: Loongson: Fix COP2 usage for preemptible kernel
        MIPS: NL: Fix nlm_xlp_defconfig build error
        MIPS: Remove race window in page fault handling
        MIPS: Malta: Improve system memory detection for '{e, }memsize' >= 2G
        MIPS: Alchemy: Fix db1200 PSC clock enablement
        MIPS: BCM47XX: Fix reboot problem on BCM4705/BCM4785
        MIPS: Remove duplicated include from numa.c
        MIPS: Add common plat_irq_dispatch declaration
        MIPS: MSP71xx: remove unused plat_irq_dispatch() argument
        MIPS: GIC: Remove useless parens from GICBIS().
        MIPS: perf: Mark pmu interupt IRQF_NO_THREAD
      497c01dd
    • Linus Torvalds's avatar
      Merge tag 'trace-fixes-v3.17-rc1' of... · 01e9982a
      Linus Torvalds authored
      Merge tag 'trace-fixes-v3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
      
      Pull fix for ftrace function tracer/profiler conflict from Steven Rostedt:
       "The rewrite of the ftrace code that makes it possible to allow for
        separate trampolines had a design flaw with the interaction between
        the function and function_graph tracers.
      
        The main flaw was the simplification of the use of multiple tracers
        having the same filter (like function and function_graph, that use the
        set_ftrace_filter file to filter their code).  The design assumed that
        the two tracers could never run simultaneously as only one tracer can
        be used at a time.  The problem with this assumption was that the
        function profiler could be implemented on top of the function graph
        tracer, and the function profiler could run at the same time as the
        function tracer.  This caused the assumption to be broken and when
        ftrace detected this failed assumpiton it would spit out a nasty
        warning and shut itself down.
      
        Instead of using a single ftrace_ops that switches between the
        function and function_graph callbacks, the two tracers can again use
        their own ftrace_ops.  But instead of having a complex hierarchy of
        ftrace_ops, the filter fields are placed in its own structure and the
        ftrace_ops can carefully use the same filter.  This change took a bit
        to be able to allow for this and currently only the global_ops can
        share the same filter, but this new design can easily be modified to
        allow for any ftrace_ops to share its filter with another ftrace_ops.
      
        The first four patches deal with the change of allowing the ftrace_ops
        to share the filter (and this needs to go to 3.16 as well).
      
        The fifth patch fixes a bug that was also caused by the new changes
        but only for archs other than x86, and only if those archs implement a
        direct call to the function_graph tracer which they do not do yet but
        will in the future.  It does not need to go to stable, but needs to be
        fixed before the other archs update their code to allow direct calls
        to the function_graph trampoline"
      
      * tag 'trace-fixes-v3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
        ftrace: Use current addr when converting to nop in __ftrace_replace_code()
        ftrace: Fix function_profiler and function tracer together
        ftrace: Fix up trampoline accounting with looping on hash ops
        ftrace: Update all ftrace_ops for a ftrace_hash_ops update
        ftrace: Allow ftrace_ops to use the hashes from other ops
      01e9982a
  4. 24 Aug, 2014 12 commits
  5. 23 Aug, 2014 5 commits
    • Heiko Stuebner's avatar
      MAINTAINERS: add new Rockchip SoC list · 00250b52
      Heiko Stuebner authored
      Add the new list that Rockchip-specific patches should also be directed to.
      Signed-off-by: default avatarHeiko Stuebner <heiko@sntech.de>
      00250b52
    • Heiko Stuebner's avatar
      ARM: dts: rockchip: readd missing mmc0 pinctrl settings · 1302d32c
      Heiko Stuebner authored
      During the restructuring of the Rockchip Cortex-A9 dtsi files it seems
      like the pinctrl settings vanished at some point from the mmc0 support.
      
      This of course renders them unusable, so readd the necessary pinctrl
      properties.
      Signed-off-by: default avatarHeiko Stuebner <heiko@sntech.de>
      1302d32c
    • Olof Johansson's avatar
      Merge tag 'sunxi-dt-for-3.17-2' of... · 2136edf3
      Olof Johansson authored
      Merge tag 'sunxi-dt-for-3.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux into fixes
      
      Merge "Allwinner DT changes, take 2" from Maxime Ripard:
      
      Only a single patch in here that fixes a DTC warning.
      
      * tag 'sunxi-dt-for-3.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mripard/linux:
        ARM: dt: sun6i: Add #address-cells and #size-cells to i2c controller nodes
      Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      2136edf3
    • Steven Rostedt (Red Hat)'s avatar
      ftrace: Use current addr when converting to nop in __ftrace_replace_code() · 39b5552c
      Steven Rostedt (Red Hat) authored
      In __ftrace_replace_code(), when converting the call to a nop in a function
      it needs to compare against the "curr" (current) value of the ftrace ops, and
      not the "new" one. It currently does not affect x86 which is the only arch
      to do the trampolines with function graph tracer, but when other archs that do
      depend on this code implement the function graph trampoline, it can crash.
      
      Here's an example when ARM uses the trampolines (in the future):
      
       ------------[ cut here ]------------
       WARNING: CPU: 0 PID: 9 at kernel/trace/ftrace.c:1716 ftrace_bug+0x17c/0x1f4()
       Modules linked in: omap_rng rng_core ipv6
       CPU: 0 PID: 9 Comm: migration/0 Not tainted 3.16.0-test-10959-gf0094b28-dirty #52
       [<c02188f4>] (unwind_backtrace) from [<c021343c>] (show_stack+0x20/0x24)
       [<c021343c>] (show_stack) from [<c095a674>] (dump_stack+0x78/0x94)
       [<c095a674>] (dump_stack) from [<c02532a0>] (warn_slowpath_common+0x7c/0x9c)
       [<c02532a0>] (warn_slowpath_common) from [<c02532ec>] (warn_slowpath_null+0x2c/0x34)
       [<c02532ec>] (warn_slowpath_null) from [<c02cbac4>] (ftrace_bug+0x17c/0x1f4)
       [<c02cbac4>] (ftrace_bug) from [<c02cc44c>] (ftrace_replace_code+0x80/0x9c)
       [<c02cc44c>] (ftrace_replace_code) from [<c02cc658>] (ftrace_modify_all_code+0xb8/0x164)
       [<c02cc658>] (ftrace_modify_all_code) from [<c02cc718>] (__ftrace_modify_code+0x14/0x1c)
       [<c02cc718>] (__ftrace_modify_code) from [<c02c7244>] (multi_cpu_stop+0xf4/0x134)
       [<c02c7244>] (multi_cpu_stop) from [<c02c6e90>] (cpu_stopper_thread+0x54/0x130)
       [<c02c6e90>] (cpu_stopper_thread) from [<c0271cd4>] (smpboot_thread_fn+0x1ac/0x1bc)
       [<c0271cd4>] (smpboot_thread_fn) from [<c026ddf0>] (kthread+0xe0/0xfc)
       [<c026ddf0>] (kthread) from [<c020f318>] (ret_from_fork+0x14/0x20)
       ---[ end trace dc9ce72c5b617d8f ]---
      [   65.047264] ftrace failed to modify [<c0208580>] asm_do_IRQ+0x10/0x1c
      [   65.054070]  actual: 85:1b:00:eb
      
      Fixes: 7413af1f "ftrace: Make get_ftrace_addr() and get_ftrace_addr_old() global"
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      39b5552c
    • Steven Rostedt (Red Hat)'s avatar
      ftrace: Fix function_profiler and function tracer together · 5f151b24
      Steven Rostedt (Red Hat) authored
      The latest rewrite of ftrace removed the separate ftrace_ops of
      the function tracer and the function graph tracer and had them
      share the same ftrace_ops. This simplified the accounting by removing
      the multiple layers of functions called, where the global_ops func
      would call a special list that would iterate over the other ops that
      were registered within it (like function and function graph), which
      itself was registered to the ftrace ops list of all functions
      currently active. If that sounds confusing, the code that implemented
      it was also confusing and its removal is a good thing.
      
      The problem with this change was that it assumed that the function
      and function graph tracer can never be used at the same time.
      This is mostly true, but there is an exception. That is when the
      function profiler uses the function graph tracer to profile.
      The function profiler can be activated the same time as the function
      tracer, and this breaks the assumption and the result is that ftrace
      will crash (it detects the error and shuts itself down, it does not
      cause a kernel oops).
      
      To solve this issue, a previous change allowed the hash tables
      for the functions traced by a ftrace_ops to be a pointer and let
      multiple ftrace_ops share the same hash. This allows the function
      and function_graph tracer to have separate ftrace_ops, but still
      share the hash, which is what is done.
      
      Now the function and function graph tracers have separate ftrace_ops
      again, and the function tracer can be run while the function_profile
      is active.
      
      Cc: stable@vger.kernel.org # 3.16 (apply after 3.17-rc4 is out)
      Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      5f151b24
  6. 22 Aug, 2014 5 commits